NZ600489A - Back-flow prevention valve for a fluid dispenser - Google Patents

Abstract

Disclosed is a back-flow prevention valve for a fluid dispenser to provide improved volume control of the dispensed fluid. The back-flow prevention valve comprises a dispensing chamber in fluid communication with a fluid reservoir or a substantially airtight container such as a bottle, a dispensing chamber inlet for fluid communication with the fluid reservoir, a dispensing chamber outlet and an actuation member or piston configured to positively displace a measured volume of fluid from the dispensing chamber through the dispensing chamber outlet. The back-flow prevention valve comprises a sealing means mounted in the dispensing chamber and adjacent to the dispensing chamber inlet and configured to seal the dispensing chamber inlet to substantially prevent fluid back-flow from the dispensing chamber back to the fluid reservoir when a positive pressure is created between the dispensing chamber inlet and the actuation member by the positive displacement of fluid by the actuation member. The actuation member is a piston shaft configured to fit within the dispensing chamber with the ability to seal either the dispensing chamber inlet or dispensing chamber outlet alternately but not both at the same time.